The right amp for my experiment

I recently saw a two piece group with a particularly innovative guitarist. He used an octaver to boost his lower end, then ran it into a bass amp and was able to craft awesome tones in the lower register. I've been thinking about using a similar technique to fill in the higher frequencies in a bass and drum project. If I were to split my signal, run one end into my bass rig and the other into a pitch shifter (I've been leaning towards the POG 2) and into my Vox AC15 guitar amp to sculpt my high end would I run the risk of damaging the guitar amp? I've been told not to run a bass into the guitar amp because the lower frequencies could damage the speaker, but if it's only being used for the upper frequencies would that still apply?